One patient has been killed and three others suffered slight injuries in an explosion at Durham Regional Hospital in central North Carolina.

Hospital operations chief Katie Galbraith says no one else was hurt in the explosion around 2:15 a.m. Tuesday on the hospital's sixth floor.

Galbraith says the hospital's sprinkler system worked properly and the fire was controlled as firefighters arrived. Other patients were moved to other parts of the hospital.

Galbraith says officials are still trying to determine exactly where the explosion occurred.

Some patients were moved because of flooding caused by the sprinkler system. She says the three patients who were slightly injured had all been on ventilators before the blast and have been taken to the intensive care unit after being checked in the emergency room.